Illuminated draftsman&#39;s guide



Aug. 7, 1951 R. w. RUSS ILLUMINATED DRAFTSMANS GUIDE Filed July 31, 1950RAYMOND W. RUSS Snventor Patented Aug. 7, 1951 UNITED STATES PATENTOFFICE 1 Claim.

This invention relates to drafting instruments and has reference tostraight and curved edges for guiding pencil points and the like whenmaking drawings.

Although most guides referred to, such as T squares, triangles,draftsmans curves and the like, either have transparent edges or aremade entirely of transparent material, they cast very pronounced shadowsalong the side of the guide remote from the source of light. Suchshadows are the cause of eye strain when the draftsman has to locatepoints falling within the shadow. It is also difficult for the draftsmanto locate such points, with the result that scale drawings are notalways as accurate as desired.

The purpose of the invention is to provide an edge for a pencil guide orthe like which will at least partially illuminate the drawing adjacentthe guide.

The invention will be more readily understood by reference to theaccompanying drawings and the following description.

Figure 1 is a perspective view of a portion of a drafting room, andshowing several guides embodying the present invention placed on adrafting board.

Figure 2 is an enlarged broken perspective of a drawing and showing atriangle embodying the invention placed thereon.

Figure 3 is a vertical sectional view of a guide made in accordance withthe invention and showing the manner in which light is transmittedthrough the guide by means of arrows.

In Figure 1, a drafting board I is positioned near a window II allowinglight passing therethrough to fall on the surface of a drawing l2. Ashadow II normally falls on the drawing I! on the side of the pencilguide, such as the triangle l4, away from the window II. A pencil guide,as herein referred to. may be any flat instrument used for guiding apencil I! along its edge when drawing lines, such as l6, H or II, andwhich guide may be in the form of the referred to triangle H, adraftsmans curve II. or a T square 2| having transparent edges 2|. Thematerial used, in accordance with the invention, is transparentfluorescent plastic of the type which absorbs light through its broadsurfaces 22 and emits light along its edges 23. The transmission oflight is best carried out when the flat surface is so smooth that itappears to be slick, and when the edges are at least slightly rough, atleast to that degree where they may be referred to as being frosted. Theguides l4 and 20 may be entirely made of the described material, or thematerial may be employed only along their edges, as shown in connectionwith the T square Hi.

The operation of the invention is best illustrated in Figure 2 where theintensity of the shadow i3 is decreased by reason of the light emittingfrom the edge 23 of the triangle H. The line is parallel with and nearthe edge 23 is sufficiently illuminated for drafting purposes. Since theedge 23 glows, there is a very marked contrast between said edge and theline l6 whereby the two may be readily distinguished for plotting pointsand the like along the line.

The present invention is not limited to the construction herein shownand described, but may be made in many ways within the scope of theappended claim.

What is claimed is:

A pencil guide for use in making drawings comprising a transparent flatbody of fluorescent plastic material having the outline of aconventional draftsmans guide, and the pencil guides edges of which areat least slightly rough.

RAYMOND W. RUSS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Hayward Aug. 18, 1942 OTHER REFERENCESNumber

